<?php
/**
 * CMysqlSchema class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2011 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CMysqlSchema is the class for retrieving metadata information from a MySQL database (version 4.1.x and 5.x).
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @version $Id: CMysqlSchema.php 3304 2011-06-23 14:53:50Z qiang.xue $
 * @package system.db.schema.mysql
 * @since 1.0
 */
class CMysqlSchema extends CDbSchema
{
    /**
     * @var array the abstract column types mapped to physical column types.
     * @since 1.1.6
     */
    public $columnTypes=array(
        'pk' => 'int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY',
        'string' => 'varchar(255)',
        'text' => 'text',
        'integer' => 'int(11)',
        'float' => 'float',
        'decimal' => 'decimal',
        'datetime' => 'datetime',
        'timestamp' => 'timestamp',
        'time' => 'time',
        'date' => 'date',
        'binary' => 'blob',
        'boolean' => 'tinyint(1)',
		'money' => 'decimal(19,4)',
    );

    /**
     * Quotes a table name for use in a query.
     * A simple table name does not schema prefix.
     * @param string $name table name
     * @return string the properly quoted table name
     * @since 1.1.6
     */
    public function quoteSimpleTableName($name)
    {
        return '`'.$name.'`';
    }

    /**
     * Quotes a column name for use in a query.
     * A simple column name does not contain prefix.
     * @param string $name column name
     * @return string the properly quoted column name
     * @since 1.1.6
     */
    public function quoteSimpleColumnName($name)
    {
        return '`'.$name.'`';
    }

    /**
     * Compares two table names.
     * The table names can be either quoted or unquoted. This method
     * will consider both cases.
     * @param string $name1 table name 1
     * @param string $name2 table name 2
     * @return boolean whether the two table names refer to the same table.
     */
    public function compareTableNames($name1,$name2)
    {
        return parent::compareTableNames(strtolower($name1),strtolower($name2));
    }

    /**
     * Resets the sequence value of a table's primary key.
     * The sequence will be reset such that the primary key of the next new row inserted
     * will have the specified value or 1.
     * @param CDbTableSchema $table the table schema whose primary key sequence will be reset
     * @param mixed $value the value for the primary key of the next new row inserted. If this is not set,
     * the next new row's primary key will have a value 1.
     * @since 1.1
     */
    public function resetSequence($table,$value=null)
    {
        if($table->sequenceName!==null)
        {
            if($value===null)
            $value=$this->getDbConnection()->createCommand("SELECT MAX(`{$table->primaryKey}`) FROM {$table->rawName}")->queryScalar()+1;
            else
            $value=(int)$value;
            $this->getDbConnection()->createCommand("ALTER TABLE {$table->rawName} AUTO_INCREMENT=$value")->execute();
        }
    }

    /**
     * Enables or disables integrity check.
     * @param boolean $check whether to turn on or off the integrity check.
     * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
     * @since 1.1
     */
    public function checkIntegrity($check=true,$schema='')
    {
        $this->getDbConnection()->createCommand('SET FOREIGN_KEY_CHECKS='.($check?1:0))->execute();
    }

    /**
     * Loads the metadata for the specified table.
     * @param string $name table name
     * @return CMysqlTableSchema driver dependent table metadata. Null if the table does not exist.
     */
    protected function loadTable($name)
    {
        $table=new CMysqlTableSchema;
        $this->resolveTableNames($table,$name);

        if($this->findColumns($table))
        {
            $this->findConstraints($table);
            return $table;
        }
        else
        return null;
    }

    /**
     * Generates various kinds of table names.
     * @param CMysqlTableSchema $table the table instance
     * @param string $name the unquoted table name
     */
    protected function resolveTableNames($table,$name)
    {
        $parts=explode('.',str_replace('`','',$name));
        if(isset($parts[1]))
        {
            $table->schemaName=$parts[0];
            $table->name=$parts[1];
            $table->rawName=$this->quoteTableName($table->schemaName).'.'.$this->quoteTableName($table->name);
        }
        else
        {
            $table->name=$parts[0];
            $table->rawName=$this->quoteTableName($table->name);
        }
    }

    /**
     * Collects the table column metadata.
     * @param CMysqlTableSchema $table the table metadata
     * @return boolean whether the table exists in the database
     */
    protected function findColumns($table)
    {
        $sql='SHOW COLUMNS FROM '.$table->rawName;
        try
        {
            $columns=$this->getDbConnection()->createCommand($sql)->queryAll();
        }
        catch(Exception $e)
        {
            return false;
        }
        foreach($columns as $column)
        {
            $c=$this->createColumn($column);
            $table->columns[$c->name]=$c;
            if($c->isPrimaryKey)
            {
                if($table->primaryKey===null)
                $table->primaryKey=$c->name;
                else if(is_string($table->primaryKey))
                $table->primaryKey=array($table->primaryKey,$c->name);
                else
                $table->primaryKey[]=$c->name;
                if($c->autoIncrement)
                $table->sequenceName='';
            }
        }
        return true;
    }

    /**
     * Creates a table column.
     * @param array $column column metadata
     * @return CDbColumnSchema normalized column metadata
     */
    protected function createColumn($column)
    {
        $c=new CMysqlColumnSchema;
        $c->name=$column['Field'];
        $c->rawName=$this->quoteColumnName($c->name);
        $c->allowNull=$column['Null']==='YES';
        $c->isPrimaryKey=strpos($column['Key'],'PRI')!==false;
        $c->isForeignKey=false;
        $c->init($column['Type'],$column['Default']);
        $c->autoIncrement=strpos(strtolower($column['Extra']),'auto_increment')!==false;

        return $c;
    }

    /**
     * @return float server version.
     */
    protected function getServerVersion()
    {
        $version=$this->getDbConnection()->getAttribute(PDO::ATTR_SERVER_VERSION);
        $digits=array();
        preg_match('/(\d+)\.(\d+)\.(\d+)/', $version, $digits);
        return floatval($digits[1].'.'.$digits[2].$digits[3]);
    }

    /**
     * Collects the foreign key column details for the given table.
     * @param CMysqlTableSchema $table the table metadata
     */
    protected function findConstraints($table)
    {
        $row=$this->getDbConnection()->createCommand('SHOW CREATE TABLE '.$table->rawName)->queryRow();
        $matches=array();
        $regexp='/FOREIGN KEY\s+\(([^\)]+)\)\s+REFERENCES\s+([^\(^\s]+)\s*\(([^\)]+)\)/mi';
        foreach($row as $sql)
        {
            if(preg_match_all($regexp,$sql,$matches,PREG_SET_ORDER))
            break;
        }
        foreach($matches as $match)
        {
            $keys=array_map('trim',explode(',',str_replace('`','',$match[1])));
            $fks=array_map('trim',explode(',',str_replace('`','',$match[3])));
            foreach($keys as $k=>$name)
            {
                $table->foreignKeys[$name]=array(str_replace('`','',$match[2]),$fks[$k]);
                if(isset($table->columns[$name]))
                $table->columns[$name]->isForeignKey=true;
            }
        }
    }

    /**
     * Returns all table names in the database.
     * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
     * If not empty, the returned table names will be prefixed with the schema name.
     * @return array all table names in the database.
     * @since 1.0.2
     */
    protected function findTableNames($schema='')
    {
        if($schema==='')
        return $this->getDbConnection()->createCommand('SHOW TABLES')->queryColumn();
        $names=$this->getDbConnection()->createCommand('SHOW TABLES FROM '.$this->quoteTableName($schema))->queryColumn();
        foreach($names as &$name)
        $name=$schema.'.'.$name;
        return $names;
    }

    /**
     * Builds a SQL statement for renaming a column.
     * @param string $table the table whose column is to be renamed. The name will be properly quoted by the method.
     * @param string $name the old name of the column. The name will be properly quoted by the method.
     * @param string $newName the new name of the column. The name will be properly quoted by the method.
     * @return string the SQL statement for renaming a DB column.
     * @since 1.1.6
     */
    public function renameColumn($table, $name, $newName)
    {
        $db=$this->getDbConnection();
        $row=$db->createCommand('SHOW CREATE TABLE '.$db->quoteTableName($table))->queryRow();
        if($row===false)
        throw new CDbException(Yii::t('yii','Unable to find "{column}" in table "{table}".',array('{column}'=>$name,'{table}'=>$table)));
        if(isset($row['Create Table']))
        $sql=$row['Create Table'];
        else
        {
            $row=array_values($row);
            $sql=$row[1];
        }
        if(preg_match_all('/^\s*`(.*?)`\s+(.*?),?$/m',$sql,$matches))
        {
            foreach($matches[1] as $i=>$c)
            {
                if($c===$name)
                {
                    return "ALTER TABLE ".$db->quoteTableName($table)
                    . " CHANGE ".$db->quoteColumnName($name)
                    . ' '.$db->quoteColumnName($newName).' '.$matches[2][$i];
                }
            }
        }

        // try to give back a SQL anyway
        return "ALTER TABLE ".$db->quoteTableName($table)
        . " CHANGE ".$db->quoteColumnName($name).' '.$newName;
    }

    /**
     * Builds a SQL statement for dropping a foreign key constraint.
     * @param string $name the name of the foreign key constraint to be dropped. The name will be properly quoted by the method.
     * @param string $table the table whose foreign is to be dropped. The name will be properly quoted by the method.
     * @return string the SQL statement for dropping a foreign key constraint.
     * @since 1.1.6
     */
    public function dropForeignKey($name, $table)
    {
        return 'ALTER TABLE '.$this->quoteTableName($table)
        .' DROP FOREIGN KEY '.$this->quoteColumnName($name);
    }
}
